My car started throwing codes for service stabilitrack, service suspension and then led to more codes for lost communications with transmission, throttle, powering down. My gauges would all go crazy and then shut off even as I was on the highway doing 65 mph. Had it to 3 dealerships over past 2 years and replaced a variety of things including ECM and BCM to no avail. Limited driving over past 2 years and spent thousands in repairs and rentals. Car was paid for and had no issues until this started happening. The car had 125K in 3 years due to work travel so once the dealer sees the miles they really don't want to get into it. I gave the car to an electrical engineer for a week and he found the problem. Rather than chasing codes he thought through the issue rationally. He checked all the modules and found the transmission module was the only one with no dialectic grease. The module and connectors tested fine but if you moved the wires the ohm meter would spike to 17 to 20 ohms and everything connecting to that module (ABS, throttle, transmission, stabilitrack) would eventually lose communication and go crazy. It was intermittent probably as I hit bumps and was less active when cold and wires were stiff. We used electrical cleaner and a nylon brush to clean any oxidation on the pins and packed with dialectic grease. It's been a month and no issue. I had named the car Christine after the movie but it's finally back to normal. All GM did was give a $1000 coupon. GM should foot the bill on this to retain my loyalty. My Dad is retired GM employee and this was a Friends and Family program car that was top of the line. These issues lead to replacing the spark plugs, flushing the engine multiple times to get rid of carbon, replacement of two catalytic converters, new ECM and BCM, and weeks of labor for the dealers not to mention my inconvenience getting stuck and needing rental cars. This fix should be a service bulletin for GM also. I've seen other complaints with the same issue. Please check the Transmission module first as it is low to the ground and liable to have more dust and dirt which can lead to these issues. I would have saved thousands if somebody had told me this fix.